The landslide struck on Wednesday and wiped out 120 workers' homes at the Meeriabedda tea estate in the central Badulla district.
Disaster Management Centre Assistant Director Pradeep Kodippili said according to the latest information 192 people were believed to be missing in the landslide at Meeriyabedda estate and rescue operations were underway.
He said 817 displaced people were being sheltered in two camps at Ampitikanda and Koslanda.
Even as top officials warned that chances of finding survivors are slim, the Army and Police personnel were engaged in rescue operations with five teams from the National Building Research Organisation (NBRO).
Sri Lanka Army has deployed a contingent of over 500 troops from the Security Forces Headquarters to rescue the buried victims of the landslide.
Together with Army soldiers, Sri Lanka Air Force troops, Policemen, health teams and civil relief teams are also currently engaged in finding about 200 people believed to be buried in the mud.
Five heavy duty trench digging machines arrived at the landslide site when the rescue operations resumed this morning.
"We are also bringing in an additional 200 troops to add to the 500 already here to carry out the search," the region's top military officer, Major General Mano Perera, told reporters.
Rescue efforts were being hampered by persistent rains that have also made the surrounding hills unstable, he said.
"There were no concrete structures which could have acted as air traps for victims to survive," he said.
Even the office which carries details of the area residents has been buried in the rubble, Disaster Management Minister Mahinda Amaraweera said.
Meanwhile, Plantation Minister Mahinda Samarasinghe on Thursday said landslide warnings issued in 2011 had been disregarded by the Meeriyabadda Tea Plantation.
An investigation must be launched against the estate owners as to why they disregarded the warning issued in 2011, which has now led to many deaths, Samarasinghe said.
NBRO said that since 2005 it had issued permanent evacuation notices to 75 families who were living in this particular location.

In addition, NBRO had also provided resettlement options and plans for these families since 2012.
However, the estate owners in charge of this area had not complied with NBRO warnings, a statement said.
"We heard a noise similar to an aircraft crashing over the hills. There was fog covering the entire area. The next we heard was the screaming from people who were buried," said Shashikala Ramiah, a resident.
M Radha, another resident, said "There was a big mound of earth on top of the lines of houses. Not a single house could be seen. I do not know the fate of my three children and my parents. At around 6:30 in the morning I heard a loud noise from the hills. Two minutes later the mountain came down with a big noise."
"A place with 63 houses completely went under the rubble, I think over 150 people lived there," S Rajagopal, another eye-witness said.

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